Re: [Xen-devel] [PATCH v2] x86/apicv: fix RTC periodic timer and apicv issue

["Xuquan (Quan Xu)" <xuquan8@xxxxxxxxxx>]

On September 26, 2016 2:39 PM, Jan Beulich < JBeulich@xxxxxxxx > wrote:
>>>> On 24.09.16 at 03:06, <xuquan8@xxxxxxxxxx> wrote:
>> On September 24, 2016 7:34 AM, Tian Kevin < kevin.tian@xxxxxxxxx > wrote:
>>>> From: Jan Beulich [mailto:JBeulich@xxxxxxxx]
>>>> Sent: Friday, September 23, 2016 11:34 PM
>>>>
>>>> >>> On 20.09.16 at 15:30, <xuquan8@xxxxxxxxxx> wrote:
>>>> > --- a/xen/arch/x86/hvm/vlapic.c
>>>> > +++ b/xen/arch/x86/hvm/vlapic.c
>>>> > @@ -433,6 +433,12 @@ void vlapic_EOI_set(struct vlapic *vlapic)
>>>> > void vlapic_handle_EOI(struct vlapic *vlapic, u8 vector)  {
>>>> >      struct domain *d = vlapic_domain(vlapic);
>>>> > +    struct vcpu *v = vlapic_vcpu(vlapic);
>>>> > +    struct hvm_intack pt_intack;
>>>> > +
>>>> > +    pt_intack.vector = vector;
>>>> > +    pt_intack.source = hvm_intsrc_lapic;
>>>> > +    pt_intr_post(v, pt_intack);
>>>>
>>>> This also sits on the EOI LAPIC register write path, i.e. the change
>>>> then also affects non-apicv environments.
>>>
>>>The new logic should be entered only when EOI-induced exit happens.
>>>
>>
>> Yes, more that the EOI-induced exit is conditional, specifically, the
>> bitmap is set by vmx_set_eoi_exit_bitmap().
>> Jan, what do you think? While I recall from v1 discussion, you have
>> the same comment. We can dig it deep..
>
>See my reply to Kevin sent a minute ago. As I'm not sure what Kevin means to
>state with several of his responses, I can't properly respond for now. And then
>what you say doesn't really address my concern - things being conditional
>elsewhere doesn't mean we won't get here too in the non-apicv case, at least
>not in a way that I can follow right away.
>

Jan, any idea now? 
Quan




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